Vaccines often underperform in Africa compared to high-income countries. Why vaccines do not work as well in Africa remains uncertain. Malnutrition likely plays a role. Our study objective is to assess whether iron deficiency anaemia in young women impairs their immune response to the COVID-19 vaccine, and whether iron treatment improves their response.

Group 1 (immediate iron treatment) will receive iron treatment before vaccination. Women in both groups will receive the 1st dose of the COVID-19 vaccine. Vaccine response will be measured 28 and 56 days after the first vaccine administration in both groups. At 28 days, participants will receive the 2nd dose of the COVID-19 vaccine. Group 2 (delayed iron treatment) will receive iron treatment at study end.

Inclusion Criteria:

18-55 years old Zinc protoporphyrin > or equal 40 mmol/mol heme hemoglobin < or equal 109 g/L no malaria no known HIV infection no medical condition that precludes study involvement no iron supplementation 1 week prior to study start no recent tuberculosis infection no vaccination of yellow fever or influenza prior to enrolment not pregnant

Exclusion Criteria:

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